“Never in a million years could I have envisioned my life going so far off the intended course.” – Scott

The Neurobiology of Sleep, Wakefulness, and Narcolepsy

The Normal Neurobiology of Sleep and Wakefulness

Optimal health and cognitive function require the coordinated activity of several systems that regulate and stabilize three distinct states: wakefulness, non-REM sleep, and REM sleep.1-5 Wakefulness usually occurs during the day, while non-REM sleep and REM sleep generally occur at night.2,3 Learn about these states and how the brain regulates them to ensure that elements of one state do not intrude into another.

The Neurobiology of Narcolepsy6,7

Narcolepsy is most often caused by the loss of hypocretin. This loss can cause insufficient activation of wake-promoting neurons and insufficient inhibition of non-REM and REM sleep-promoting neurons, leading to sleep-wake state instability.1,3,8,9 The boundaries between wakefulness, non-REM sleep, and REM sleep become unstable, allowing elements of one state to intrude into another, and the transitions between states to become frequent and unpredictable.1,4,8-10

The Role of Histamine in Sleep and Wakefulness

In the CNS, histamine neurons originate only in the hypothalamus and are thought to play an important role in the regulation of sleep-wake state stability.1,3,11 Learn how histamine has been shown to play an important role in regulating sleep-wake states.

Sudden and brief loss of muscle strength or tone, often triggered by strong emotions. Narcolepsy with cataplexy is known as type 1 narcolepsy.

Complete collapse to the ground; all skeletal muscles are involved.

Only certain muscle groups are involved.

Biological clock mechanism that regulates the 24-hour cycle in the physiological processes of living beings. It is controlled in part by the SCN in the hypothalamus and is affected by the daily light-dark cycle.

Frequent inappropriate transitions between states of sleep and wakefulness.

The inability to stay awake and alert during the day.

A neurotransmitter that supports wakefulness. The TMN is the only source of histamine in the brain.